Everting sleeve devices for probing internal body cavities, for delivering drugs in powder form to the surfaces of those cavities and for taking samples from within the cavity are well known in the medical arts. Attention is directed to U.S. Pat. Nos. 3,168,092 issued Feb. 2, 1965, No. 3,500,819 issued Mar. 17, 1970 and No. 3,589,356 issued Jun. 29, 1971, all to Daniel Silverman, which are typical of the prior art everting sleeve devices. Essentially, a cylindrical external casing is provided with a long thin walled plastic tubing which is anchored at one end thereof to the inside wall of the casing and extends along the inside of the casing. The tubing may be open- or closed-ended. By application of external gas pressure between the casing and the tubing, the tubing is forced to turn on itself, or evert, and extend outwardly beyond the end of the casing. Powdered drugs may be applied to the everting surfaces before use and these will be deposited on the mucosa or walls of the body cavity as the tubing extends. If an open-ended tubing is employed, samples of body fluids or the like may be withdrawn through the extended tubing. Withdrawal of the tubing may be effected by withdrawing the tubing in its extended condition or by re-everting the tubing by pulling on an internally mounted withdrawal cord or the like. These prior art devices, while relatively effective, suffer from several serious disadvantages. Firstly, considerable pressure is required to evert the tubing and in the event that the tubing should fail during eversion considerable damage to sensitive and delicate body tissues may result. Secondly, withdrawing an extended tubing from a body cavity may cause considerable friction and hence discomfort or pain to the patient. Everting the extended tubing by means of an internal withdrawal cord or the like is cumbersome and not very practical in the case of very thin long tubes. There is a need, therefore, for an improved everting sleeve-type device for delivering powdered drugs and the like to long narrow body passages, such as, but not limited to, the urethra, bladder, vagina, anus, rectum and colon.